package com.msl.debezium.common;

import org.apache.commons.lang3.StringUtils;

import javax.crypto.*;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

public class AesUtil {

    public static final String CIPHER = "DEBE-AES-258";

    /**
     * 加密
     * @param content 需要加密的内容
     * @return
     */
    public static String encrypt(String content) {
        try {
            // 创建密码器
            Cipher cipher = Cipher.getInstance("AES");
            // 初始化密码器
            KeyGenerator kgen = KeyGenerator.getInstance("AES");
            kgen.init(128, new SecureRandom(CIPHER.getBytes()));
            SecretKey secretKey = kgen.generateKey();
            byte[] enCodeFormat = secretKey.getEncoded();
            SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
            cipher.init(Cipher.ENCRYPT_MODE, key);
            //加密
            byte[] byteContent = content.getBytes("utf-8");
            byte[] result = cipher.doFinal(byteContent);
            // 二进制转换成16进制
            return parseByte2HexStr(result);
        } catch (NoSuchAlgorithmException e) {
                e.printStackTrace();
        } catch (NoSuchPaddingException e) {
                e.printStackTrace();
        } catch (InvalidKeyException e) {
                e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
                e.printStackTrace();
        } catch (BadPaddingException e) {
                e.printStackTrace();
        }
        return null;
    }
    /**
     * 解密
     * @param content  待解密内容
     * @return
     */
    public static String decrypt(String content) {
        try {

            // 创建密码器
            Cipher cipher = Cipher.getInstance("AES");
            // 初始化
            KeyGenerator kgen = KeyGenerator.getInstance("AES");
            kgen.init(128, new SecureRandom(CIPHER.getBytes()));
            SecretKey secretKey = kgen.generateKey();
            byte[] enCodeFormat = secretKey.getEncoded();
            SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
            cipher.init(Cipher.DECRYPT_MODE, key);
            //将16进制转换为二进制，解密并返回
            byte[] contentByte = parseHexStr2Byte(content);
            byte[] result = cipher.doFinal(contentByte);
            return new String(result);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 将二进制转换成16进制
     * @param buf
     * @return
     */
    public static String parseByte2HexStr(byte buf[]) {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < buf.length; i++) {
                String hex = Integer.toHexString(buf[i] & 0xFF);
                if (hex.length() == 1) {
                        hex = '0' + hex;
                }
                sb.append(hex.toUpperCase());
        }
        return sb.toString();
    }

    /**
     * 将16进制转换为二进制
     * @param hexStr
     * @return
     */
    public static byte[] parseHexStr2Byte(String hexStr) {
        if (hexStr.length() < 1)
                return null;
        byte[] result = new byte[hexStr.length()/2];
        for (int i = 0;i< hexStr.length()/2; i++) {
                int high = Integer.parseInt(hexStr.substring(i*2, i*2+1), 16);
                int low = Integer.parseInt(hexStr.substring(i*2+1, i*2+2), 16);
                result[i] = (byte) (high * 16 + low);
        }
        return result;
    }

}
